What is a site map?
A site map is a schematic representation of a web site showing home page, zone pages and other constituent parts of a web site and the relationship between the various parts including, specifically, links between pages.
Why are site maps so important?
For human beings (site visitors) a site map enables visitors to navigate to a specific zone or page quickly. Instead of having to back out to the home page or access the navigation bar, visitors can click on the site map link and have available all pages with links to each one.